1. Field of the Invention
The invention relates, in other words to a device for measuring the xenon concentration designed to be integrated in anesthesia apparatus (integrated system), the respiratory anesthesia apparatus comprising a main circuit for leading a gas flow for administering to the patient an anaesthetic gas mixture containing xenon, and a respiratory system for ventilating the anesthetized patient.
2. Related Art
Many respiratory anesthesia apparatuses are known that can be used for producing anesthesia of a patient who has to undergo a surgical operation or the like, by administering to him or her a conventional anaesthetic gas mixture by inhalation, composed of N2O, halogenated agents (for example Sevoflurane, Isoflurane, Desflurane). In this connection, reference may be made for example to documents EP-A-983 771 and EPA-A-1 120 126.
Among the gas mixtures that may be used, those based on xenon will be increasingly used with indications particularly suited to delicate patients (elderly patients, long operations, cardiac surgery, neurosurgery, etc.) on account of, in particular, the virtually zero influence on blood pressure during anesthesia and the absence of secondary and harmful effects from xenon.
However, anesthesia carried out with xenon requires xenon concentrations in the gas flow administered to the patient to be followed or monitored, that is to say it requires the ability to determine in real time the xenon concentration in the anesthetic flow.
To this end, reference may be made for example to documents EP-A-1 499 377, EP-A-1 318 797 or EP-A 523 315.
At the present time, a mass spectrometer or chromatograph is conventionally used for measuring a xenon concentration in such a gas mixture.
Now, these techniques have disadvantages regarding cost and especially the difficulty of implementing them, since their integration into existing anesthesia apparatuses requires very considerable development and adaptation efforts.